//
//  CZMainTabBar.swift
//  GZWeibo009
//
//  Created by gzxzmac on 16/3/19.
//  Copyright © 2016年 gzxzmac. All rights reserved.
//

import UIKit

// TabBarItem个数
let TabBarItemCount = 5

class CZMainTabBar: UITabBar {
    
    // 1.闭包属性
    var composeButtonCallback: (() -> ())?

    override func layoutSubviews() {
        super.layoutSubviews()
        
//        print("CZMainTabBar: layoutSubviews")
        
        // 计算 item的宽度
        let width = frame.width / CGFloat(TabBarItemCount)
        
        // 计算最左边的这个frame,后面使用CGRectOffset
        let originFrame = CGRect(x: 0, y: 0, width: width, height: frame.height)
        
//        print("subViews: \(subviews)")
        var index = 0
        for view in subviews {
            // 判断是否是 UITabBarButton
            if view.isKindOfClass(NSClassFromString("UITabBarButton")!) {
                // 设置每个UITabBarButton的位置
//                view.frame = CGRect(x: CGFloat(index) * width, y: 0, width: width, height: frame.height)
                
                // rect: 原始的frame
                // dx: x方向的偏移量
                // dy: y方向的偏移量
                view.frame = CGRectOffset(originFrame, CGFloat(index) * width, 0)

                index += index == 1 ? 2 : 1
//                index++
//                if index == 2 {
//                    index++
//                }
            }
        }

        // 设置加号按钮frame
        composeButton.frame = CGRect(x: 2 * width, y: 0, width: width, height: frame.height)
    }
    
    // MARK: - 按钮点击事件
    func didClickComposeButton() {
        // 2.调用闭包
        composeButtonCallback?()
    }
    
    // MARK: - 懒加载
    /// 加号按钮
    private lazy var composeButton: UIButton = {
        let button = UIButton()
        
        // 设置
        button.setBackgroundImage(UIImage(named: "tabbar_compose_button"), forState: UIControlState.Normal)
        button.setBackgroundImage(UIImage(named: "tabbar_compose_button_highlighted"), forState: UIControlState.Highlighted)
        
        button.setImage(UIImage(named: "tabbar_compose_icon_add"), forState: UIControlState.Normal)
        button.setImage(UIImage(named: "tabbar_compose_icon_add_highlighted"), forState: UIControlState.Highlighted)
        
        button.addTarget(self, action: "didClickComposeButton", forControlEvents: UIControlEvents.TouchUpInside)
        
        // 添加到tabBar上面
        self.addSubview(button)
        
        return button
    }()
}
